1. Field of the Invention
This invention relates to a number of interrelated improvements for a railway system which employs a linear synchronous motor as its means of propulsion. More specifically, it relates to improved means for controlling the air gap between the moving and stationary motor parts of the linear synchronous motor by controlling the relationship between the moving motor parts of the motor and the wheels supporting the railway cars using the railway system, and also by controlling the relationship between the stationary motor parts of the linear synchronous motor and the rails upon which the wheels of the railway cars ride. It also relates to a means for controlling the air gap between the moving and stationary motor parts of the linear synchronous motor at switching points on the railway system by controlling the angular orientation of the moving motor parts of the linear synchronous motor relative to the wheels of the railway cars upon which these moving motor parts are mounted. This angular orientation through a switching point is designed to match the angular orientation of the stationary motor parts of the linear synchronous motor relative to the rails upon which the railway car rides through a switching point regardless of the direction taken by the railway car at the switching point.
2. Description of the Prior Art
Linear synchronous motors offer a number of important advantages with regard to their use as propulsion systems for ground transportation systems. They can be operated at extremely high speeds, with the limit generally being dictated by the method of supporting the vehicles on the track, rather than by the capabilities of the motors themselves; they are extremely efficient motors, offering great savings in fuel consumption; and they are capable of operation at constant speeds of travel which are determined solely by the frequency of the applied alternating current, thus offering potential for absolute vehicle speed control and consequent extremely high traffic capacities.
Utilization of the high efficiency offered by linear synchronous motors depends on the maintenance of a narrow air gap between the moving and stationary motor parts of the motors. At high speeds of travel, vehicles are subject to increased probabilities of deviation from a constant plane of orientation, due to increased dynamic forces. Thus, it is very important that all geometric factors affecting the relative positions of the moving and stationary motor parts be carefully controlled. If we take as an example a railway system employing railway cars mounted on wheels running on rails, and powered by an overhead linear synchronous motor, then it becomes critical for the maintenance of a small and relatively constant air gap between the moving and stationary parts of that motor, that both the vertical distance between the bottoms of the railway car wheels and the tops of the moving motor parts, and the vertical distance between the tops of the rails and the bottoms of the stationary motor parts be controlled within strict limits.